Red Blood Cell Dynamics in Healthy and Cancer-Influenced Venular Flow: Role of Flow Conditions and Cell Stiffness.

BACKGROUND

Hemodynamic alterations in microvessels under pathological conditions such as cancer can modify RBC dynamics and near-wall behavior, influencing the cell-free layer and local flow microenvironment.

METHODS

Three-dimensional simulations of two red blood cells with different stiffness levels were performed in venular flow under conditions representing a healthy individual and a breast cancer patient. The simulations were carried out using a force-coupling immersed-boundary lattice Boltzmann framework. RBC deformation, longitudinal and radial migration, velocity distribution, shear rate, and pressure fields were analyzed using hematocrit data, with blood viscosity derived from these data.

RESULTS

Compared with healthy flow, cancer-affected conditions led to reduced RBC deformation and diminished radial migration, resulting in increased near-wall residence. This effect was more pronounced for the stiffened RBC. It was accompanied by a local reduction in near-wall velocity, an increase in shear rate, and larger pressure differences across the cell. Shear rate was higher in cancer-affected flow, while near-wall variations were reduced.

CONCLUSIONS

The results indicate that cancer-associated changes in venular flow promote RBC near-wall localization and may suppress CFL formation, primarily due to reduced RBC deformation, overriding low-hematocrit dilution. Circulating tumor cells were not modeled; however, RBC dynamics suggest a microenvironment that may facilitate near-wall interactions.